1. Field of the Invention
The present invention relates to an integrated sintered body having a sintered phase comprising yttrium-aluminum garnet and a method of producing the same.
2. Related Art Statement
In a semiconductor manufacturing system in which a super-clean state is necessary, halogen-based corrosive gases such as chlorine-based gases and fluorine-based gases are used as a deposition gas, an etching gas and a cleaning gas. For instance, in a semiconductor manufacturing system such as thermal CVD system, after the deposition, semiconductor cleaning gases composed of halogen-based corrosive gases such as ClF3, NF3, CF4, HF and HCl are used. Furthermore, in the film deposition step, halogen-based corrosive gases such as WF6, SiH2Cl2 and so on are used as gases.
It is thus desired that the members for use in a semiconductor manufacturing apparatus, for instance, members that are accommodated in the apparatus and an inner wall surface of a chamber, are provided with a coating that is highly corrosion-resistant against a halogen gas and its plasma and which are stable over a long period of time.
The assignee disclosed, in JP 2002-249864A, that when an yttria-alumina garnet film is formed on a surface of a substrate by use of a spraying method, excellent corrosion resistance against plasma of a halogen gas can be endowed and particles can be suppressed from generating. In plasma spraying process, however, it is difficult to form a film having a thickness over a relatively low limit, such as 0.5 mm.
The assignee also filed a Japanese patent application 2002-165, 100, and disclosed a process of forming yttrium-aluminum garnet film on the surface of an alumina substrate by applying gel casting.
The inventors have further studied the above process, and found the following problems. That is, as the thickness of the yttrium-aluminum garnet film is made larger, cracks may occur in the film which increase the incidence of products having the film peeled from the underlying alumina substrate. Such cracks and peeling reduce the production yield.